It is know that non-ferrous alloys attack the structural steel of rollers working within the alloys, wherein the rollers are provided for guiding the steel band being coated with the alloys. It is also known that this attack of the alloys against the rollers limits the useful life of the rollers to only a few days, due to the building up of intermetallic alloys of the bath upon the roller steel on the roller surfaces. This accumulation upon thickening of the alloys produces protuberances, and deformations of the original cylindrical shape of the rollers. These protuberances and deformations alter the plane of the steel sheet being coated, which is the reason why rejections of the final steel sheet product occur, which causes frequent production shutdowns for replacing of the rollers.